Ground surface debris collection mat

ABSTRACT

A mat for sweeping a surface, formed of grid-like, semi-flexible material. The mat is pulled over the surface to effect the sweeping. The material has open slots ( 112   a,    112   b ) therethrough. The slots have a leading edge and a trailing edge disposed transversely relative to the direction of travel of the mat. Ground debris can pass upwardly through each slot, over the respective trailing edge to collect on an upper surface of the mat. Over the upper surface, the grid-like material defines an array of first apertures ( 136 ). At least a substantial proportion of the first apertures ( 136 ) have within them second apertures ( 146 ) of smaller size than the first apertures.

BACKGROUND OF THE INVENTION

[0001] (i) Field of the Invention

[0002] This invention relates to a mat for collecting debris such asleaves and sticks, from a surface, such as the surface of a tenniscourt.

[0003] (ii) Prior Art

[0004] Outside playing courts, such as tennis courts, are often prone toaccumulating leaves or other debris on their surface which must beperiodically removed.

[0005] Australian patent 628556 describes a mat for sweeping a surface,the mat comprising slots through which debris, such as leaves or sticks,can pass to collect on the upper surface of the mat.

[0006] The mat may be composed of a semi-flexible material, such asrubber or a suitable polymeric material.

[0007] The slots may be elongate with the longitudinal axis of each slotfacing generally in the direction of travel of the mat. The trailingedge of each slot may be chamfered to lift debris onto the upper surfaceof the mat. The trailing edge of each slot may face perpendicularly tothe direction of travel or may be inclined, for example at 45°. In themat, all of the slots may be inclined to the direction of travel, orsome may be inclined with others being perpendicular to the direction oftravel.

[0008] In one particularly advantageous form, the mat is of a grid-likeconstruction for “bagging” a clay tennis court, with portions of thegrid being removed to define the slots. Thus “bagging” of the courtperiodically during play will also serve to remove leaves and otherdebris from the surface of the court.

[0009] In a particular form, the mat is of grid-like construction,presenting an array of apertures, typically of rectangular form, andabout 12.5 mm side dimension, arranged with sides at about 45° to theintended direction of travel of the mat.

[0010] Arrangements as above described have been found particularlyuseful for, among other things, sweeping debris from tennis courts. Ithas now been found that by forming the unslotted part of the mat in aparticular way, improved operation is achieved when cleaning certaincourt surfaces.

SUMMARY OF THE INVENTION

[0011] In one aspect, the invention provides a mat for sweeping asurface, the mat having slots through which debris can pass to collecton the upper surface of the mat, as the mat is passed over a surface tobe swept, the mat being formed as a perforate structure having an arrayof first apertures therethrough, and within at least a substantialproportion the first apertures, mesh structures which, within therespective first aperture, present a respective array of secondapertures of substantially smaller size than the first apertures.

[0012] The first apertures may for example be about 150 mm in area, andthe second apertures may be in the range 2.25 to 25 mm², such as 9 or 10mm². The first apertures may be formed by a grid-like structure having,for example, intersecting sets of parallel walls which cross at anangle, such as 45°. The first apertures may then be rectangular, such assquare. The second apertures may be similarly formed, the meshstructures defining opposed sets of transversely disposed elementsextending between opposed walls of the respective first aperture. Theseelements forming the mesh structure may conveniently extend parallel toopposed ones of the walls defining the first apertures.

[0013] Preferably, the elements defining the second apertures aredisposed at locations at or towards the bottom edges of the walls. Bythis, the walls extend upwardly around the second apertures in eachfirst aperture.

[0014] Preferably, too, the second apertures are present in asubstantial portion at least, preferably all, of the first aperturesspaced away from the trailing edges of at least a substantial proportionof, preferably all, the slots, and not present in at least a substantialproportion, preferably all, of the first apertures adjacent the trailingedges of the slots.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0015] The invention is further described by way of example only withreference to the accompanying drawings in which:

[0016]FIG. 1 is a diagrammatic plan view of a mat in accordance withAustralian patent 628556 and having slots for collecting the debris;

[0017]FIG. 2 is a perspective view of an enlarged scale showing part ofthe trailing edge of one of the slots;

[0018]FIG. 3 is a plan view of a mat element formed in accordance withthe invention;

[0019]FIG. 4 is a side view of the mat element of FIG. 3;

[0020]FIG. 5 is a perspective view of a mat element like that in FIG. 3but incorporating a modification;

[0021]FIG. 6 is a plan view of a modified form of mat as described inAustralian patent 628556;

[0022]FIG. 7 is a perspective view of a mat element forming part of themat of FIG. 6;

[0023]FIG. 8 is a partly diagrammatic plan view of another form of matelement described in Australian patent 628556;

[0024]FIG. 9 is a top view of a mat element, similar to that shown inFIGS. 3 and 4, but modified in accordance with the teaching of thisinvention; and

[0025]FIG. 10 is a fragmentary view on the line 10-10 in FIG. 9.

DETAILED DESCRIPTION

[0026] The forms of mat shown in FIGS. 1 to 8 are first described.

[0027] As shown in FIGS. 1, a mat for bagging a clay tennis courtcomprises a grid-like, semi-flexible material. Preferably, the mat iscomposed of rows of separately formed rectangular elements 4 eachcomprising an outer border 6 which surrounds a grid-like formation 7,with the axes of the grid extending approximately at 45° to the edges ofthe element 4. The elements 4 are fastened together to form the mat bylugs projecting from the border 6 of one element to fit into holescorrespondingly formed in the adjacent border of the adjacent element. Astrip 8 at the leading edge of the mat a rope-like handle 10 by whichthe mat can be dragged along the surface of the court.

[0028] At least some of the elements 4 have elongate slots 12 formedwithin the grid-like formation 7. It is not necessary to put theelongate slots 12 in the first row 14 of elements 4 forming the mat asthis row is usually lifted at least partially few the court in thedragging action, but preferably each of the other elements is providedwith a slot 12. It is not, however, essential for all of the otherelements to be provided with slots and satisfactory results may beobtained if only some of the other elements have slots suitablydistributed along the length and width of the mat.

[0029] The longitudinal dimension of each slot 12 is in this caseparallel to that of the grid. Preferably the slots 12 of adjacentelements in the same row are oppositely inclined to define aherringbone-like pattern. Alternatively, some or all of the slots 12 maybe substantially at right angles to the direction of travel.

[0030] As shown in FIG. 2, the training edge 16 of each slot 12 ischamfered by shaping the projecting edge portion 18 of the grid 7 whichextends into the slot. As shown this forms forwardly projecting fingerelements 18 a. The chamfer of the trailing edge facilitates lifting ofthe debris onto the upper surface of the mat. The leading edge 20 ofeach slot 12 may also be chamfered.

[0031] In a modified embodiment having slots inclined to the directionof travel the projecting edge portion 18 of the grid 7 may be angled soas to be aligned directly in the direction of travel of the mat. Thelower edge 22 of the projecting edge portion 18 may also extend belowthe lower surface of the grid 2 to further facilitate the lifting actionof the debris onto the upper surface of the mat.

[0032] As the mat is dragged along a clay court in order to bag thesurface, his will also have the effect of collecting the debris, such asleaves, from the court by passing through the slots onto the uppersurface of the mat. Although all of the debris will not necessarily becollected in a single pass, successive baggings of the court will serveto completely remove all of the debris. The slots also act to reduce thefrictional drag of the mat.

[0033] Although the mat particularly described is primarily designed fora clay court in order to remove debris while bagging the court, the matcan also be used on a synthetic grass court or other grassed surfaces,such as lawns or playing fields, just for the purpose of removing leavesor other debris. The mat has also proven effective in gathering leavesand other debris on hard surfaces, such as concrete and “Plexipave”.

[0034] The mat may also be used to sweep a beach or other surface inorder to remove debris. For this purpose the mat need not necessarily beof grid-like construction. When the debris is likely to consist ofbottles and other relatively larger matter, the slots will be of anappropriate size to accommodate this.

[0035] The mat element 4 a of FIG. 3 and the element 4 b of FIG. 5 aregenerally similar to that of FIGS. 1 and 2 and like reference denoteslike parts in FIGS. 1, 2, 3, 4 and 5.

[0036] In these instances, the slots 12 extend from side to side of theelements, while front to rear extending central strengthening ribs 30are provided. FIGS. 3, 4 and 5 also show co-operating protrusions 32 andrecesses 34 on the outer borders 6 which permit snap fitting of theelements together to form the mat.

[0037] In FIG. 5 the element 4 b has a row of upstanding projections 36at the part of grid-like formation defining the front edge of slot 12.These assist in the action of retaining picked up debris on theformation 7. They may be provided at additional or alternative locationson the elements 4, 4 a, 4 b such as at side edges or on the rear part ofthe formation 7. More than one row, such as staggered rows of these maybe provided. The projections may be of spigot-like form, as shown, ormay be otherwise formed such as by upstanding fence-like structures. Themodified mat shown in FIG. 6 is of similar form to that of FIG. 1, butthe component elements 4 c are here of hexagonal form, as best shown inFIGS. 7, with the slots 12 extending at 90° to front to rear extendingparallel side portions 6 a, 6 b of the border 6.

[0038] The elements 4 c snap fit together in similar fashion to elements4, 4 a, 4 b. As shown, upstanding projections 36 are again provided inthis instance. The forward portions of the elements 4 c may be lefttogether to present a saw-tooth like front edge to the mat, but weprefer to cut portions 40, 42 a, 42 b, 44 a, 44 b from elements 4 c andsnap fit them to the elements in the mat to form a straight edged mat.In this case, too, the elements are again provided with the front torear extending strengthening ribs 30, these extending from front to rearpointed ends of the elements.

[0039] The mat element 4 d of FIG. 8 is somewhat similar to that ofFIGS. 6 and 7.

[0040] The mat elements 4 c and 4 d have the slots 12 positioned mid waybetween front and rear ends thereof, but these slots may be positionedcloser to the front or rear ends. The former is shown in FIGS. 6, 7 and8. In any event, as shown, the slots in side-by-side elements 4 c or 4 dmay be aligned in the side to side direction of the mat.

[0041] The described mat is formed from, for example, plastics materialsbut could be formed from other materials. For example, it may be formedfrom relatively hard material such as metal. Preferably though even inthis case it should form a relatively flexible and/or resilientstructure. In any event too, the structure, however formed, may be ofdifferent scale, such as larger, than the sizes employed in theexemplary constructions which are designed mainly for use on tenniscourts with total side to side dimensions of the order of two or threemeters. The term “mat” as used in this specification is to be understoodas encompassing such differently constructed or differently sizedstructures.

[0042] Referring now to FIG. 9, there is shown therein a top view of amat element 104 constructed in accordance with this invention. This issimilar to the mat element 4 a shown in FIGS. 3 and 4 in that it isformed of a grid-like semi-flexible material. In particular, the element104 has an outer border element 106 with a substantial part of theinterior within the border element being formed as a grid-like structure107. The grid-like structure 107 is formed of a series of parallel walls120 which are arranged to extend transversely to another series ofparallel walls 124 with the walls 120 being transverse and, in thiscase, normal to the walls 124. This grid-like structure is present overa leading edge portion 140 of the element 104 and also over a trailingedge portion respectively adjacent to forward and rear portions 154 and156 of the outer border element 106. The walls 120, 124 may be of asimilar form to corresponding walls defining the grid-like structure inFIG. 3, as evident, for example in FIG. 5. These walls are of somewhatrectangular cross-section, elongate the vertical direction. They mayextend at angles of 45° to the direction of travel “A” of the mat.

[0043] As shown, the portion 140 extends only about {fraction (1/10)} ofthe length of the mat element 104 reckoned in the direction of travel“A” of the mat. Portion 140 is bounded, as mentioned, at its forward endby border element portion 154 and is also bounded at its rear end by atransverse wall 160. The portion 144 is bounded at a forward end bytransverse wall 162 and at its rear end by portion 156 of the borderelement 106. Portion 144 occupies about a half of the lengthwisedimension of the element 104. Between the walls 160 and 162, there isdefined an elongate side-to-side extending slot 112 which is divided atthe centre thereof into two portions 112 a 112 b by a strengthening pairof forward to rearward extending ribs 164, 166, which also extendthrough portions 140 and 144 to join with forward and rearward portion154, 156 of border element 106.

[0044] Finger elements 128 extend forwardly in parallel disposition fromwall 162 into the slot 112 about 30% of the dimension of the slot 112 inthe forward to rearward direction. These may be formed in the same wayas fingers 18 in the embodiment of FIGS. 3 to 5.

[0045] The grid-like pattern of the grid structure 107 from which themat element 104 is formed defines an array of first apertures 136 eachbounded at two opposed sides by parts of adjacent walls 120 and of theother two sides by parts of adjacent walls 124. These first apertures136 may be of dimension 12.5 by 12.5 mm.

[0046] In accordance with the teachings of the invention, there areprovided over a substantial proportion of the first apertures 136 in theportion 144 of the mat element 104, mesh structures 138 which divide therespective first apertures into a number of smaller second apertures146. In this case nine such second apertures 146 are provided in asubstantial proportion of the first apertures which are positioned in apart 148 of portion 144 of the mat element 104, being that part whichextends forwardly from the wall portion 156 to a transverse line about 2cm behind the wall 162. That is to say the first apertures at a part 150immediately behind the wall 162 and thus immediately behind the slot 112are left with first apertures 136 which do not have therewithin the meshstructures 138. As shown, the mat element 104 has side to side extendingdownwardly depending bars 145 at its underside, and a forward one ofthese is at the boundary between parts 148, 150.

[0047] As shown, the mesh structures 138 each comprise two elongateelements 152 which extend in spaced parallel disposition parallel towalls 120 of the grid structure, and two similar parallel elements 158which extend transversely thereto and parallel to walls 124 of thegrid-like structure 107. The resultant second apertures 146 are thussquare. As shown in FIG. 10, mesh structures 138 may be positioned atlower portions of the walls 120, 124 so that those portions of the walls120, 124 surround the mesh structures and extend upwardly therefrom.

[0048] The second apertures 146 are in the described arrangement of areaof roughly {fraction (1/9)} to {fraction (1/10)} the area of the firstapertures. They may, for example, be of dimension 1.5×1.5 mm. Generally,it has been found that dimensions providing areas of 2.25 up to 25 mm²are satisfactory. An optimum size for many tennis court cleaningapplications has been found to be about 4 mm². In the illustratedconstruction, the areas of the second apertures are about 9 mm, allowingfor the thickness of the elements 152, 158. Generally, the secondapertures are preferably substantially smaller than the first apertures,such as {fraction (1/10)} of the area of these.

[0049] The mat element 104 can be used to form a mat in the same way asdescribed previously in relation to the previous mat elements.

[0050] Extensive testing has shown that arrangements as described with arelatively coarse mesh screen provided by the overall mesh structure107, together with a fine mesh provided by the mesh structures 138enables the mat to remove small particles of debris such as gum nuts andhusks, small flowers, small stones and solon and to pick them upsuccessfully while still allowing court surfacing material such as finesand and crushed brick to fall back onto the court.

[0051] It has been found that leaving the part 150 without meshstructures 138 assists in preventing clogging, since there is otherwisea tendency for particulate material from the surface to collect in thosefirst apertures and block them completely, interfering with the actionof cleaning, While not shown, the mesh structures 138 are preferablyalso provided in the first apertures at the forward portion 140.

[0052] It has also been found that the positioning of the meshstructures 138 at the bottom of the grid-like structure provided bywalls 120, 124 (FIG. 10) assists in directing collected material to themesh structures 138 and while still facilitating trapping of largerdebris.

[0053] Particularly in the case where the structures 138 are as shown inFIG. 10 at the bottom of the walls 120, 124 defining the grid-likestructure 145 it is preferred that structures such as the mentioned bars145 be provided to maintain the lower surface of the grid-like structure107 above the ground surface to be swept. This allows particles passingdownwardly through the mesh structures 138 to be easily returned to theground surface.

[0054] In an alternative embodiment (not shown) the mesh-like structure107 is not present. In this case, for example, the mat element 104 whichforms the portions 140 and 144, which are however simply formed fromperforate material. In this case, the outer border element 106 may stillbe provided with the remainder of the mat for example being formedwholly or partly from a suitable perforate material. In this case, it ispreferred that the bars 145 still be provided, for the purposepreviously described, and also to provide structural reinforcement. Inthis case, there need be no first apertures, only second apertures 146.As before, the second apertures are preferably of area in the range 2.25mm² to 25 mm², such as 9 or 10 mm² as described.

[0055] The described construction has been advanced merely by way ofexplanation and many modifications and variations may be made theretowithout departing from the spirit and scope of the invention as definedin the appended claims.

[0056] Throughout this specification and the claims which follow, unlessthe context requires otherwise, the word “comprising”, and variationssuch as “comprises” and “comprising”, will be understood to imply theinclusion of a stated integer or step or group of integers or steps butnot the exclusion of any other integer or step or group of integers orsteps.

The claims defining the invention are as follows:
 1. A substantiallyflat mat of grid-like material, for sweeping a surface by pulling themat over the surface in a direction of travel substantially transverseto a leading edge of the mat, the mat having at least one slot extendingtherethrough and disposed transversely relative to the direction oftravel, whereby in use of the mat debris can pass through the slot overa trailing edge thereof to collect on an upper surface of the mat;wherein said grid-like material defines at said upper surface an arrayof first apertures, at least a substantial proportion of said firstapertures have therein second apertures of smaller size than the firstapertures.
 2. A mat as claimed in claim 1 formed of hard material.
 3. Amat as claimed in claim 2 , wherein said material is metal.
 4. A mat asclaimed in claim 1 composed of a semi-flexible material.
 5. A mat asclaimed in claim 4 , wherein said semi-flexible material is rubber or apolymeric material.
 6. A mat as claimed in claim 1 , wherein the tailingedge of the slot is chamfered for facilitating lifting of debris ontothe upper surface of the mat.
 7. A mat as claimed in claim 6 , whereinthe trailing edge of the slot is perpendicular to the direction oftravel of the mat.
 8. A mat as claimed in claim 6 , wherein the trailingedge of the slot is inclined to the direction of travel of the mat.
 9. Amat as claimed in claim 8 , wherein the trailing edge of the slot isinclined at 45° to said direction of travel.
 10. A mat as claimed inclaim 8 or claim 9 , wherein the mailing edge of the slot is providedwith finger elements projecting in the direction of travel of the mat.11. A mat as set forth in claim 10 , wherein said grid-like material ofsaid mat provides a debris support formation rearwardly of said slothaving upper and lower surfaces and wherein said finger elements have anupper surface which slopes downwardly toward said leading edge of saidslot and wherein a lower surface of said finger elements extends belowsaid lower surface of said support formation.
 12. A mat as claimed inany preceding claim, wherein a plurality of said slots are provided,said slots extending transverse to the direction of travel.
 13. A mat asclaimed in claim 1 , wherein said slot is sidewardly elongated.
 14. Amat as claimed in claim 1 formed of elements of generally rectangularconfiguration affixed to each other at edges thereof.
 15. A mat asclaimed in claim 1 , wherein upstanding barrier means is provided forretaining collected debris on said upper surface of the mat.
 16. A matas claimed in claim 15 , wherein said barrier means has at least onetransverse row of upstanding projections.
 17. A mat element for forminga mat for sweeping a surface, said mat element comprised of asubstantially flat, grid-like material, the mat element having an openslot therethrough, having a leading edge and a trailing edge, said matelement having connection means thereon for connection to other matelements to provide a mat adapted to be dragged over a surface in adirection of travel transverse to said elongated slot whereby debris canpass through said slot to collect on an upper surface of the matelement; wherein said grid-like material defines an array of firstapertures, at least a substantial proportion of said first apertureshaving therein second apertures of smaller size than the firstapertures.
 18. A mat element as claimed in claim 17 formed of hardmaterial.
 19. A mat element as claimed in claim 18 , wherein saidmaterial is metal.
 20. A mat element as claimed in claim 17 composed ofa semi-flexible material.
 21. A mat element as claimed in claim 19 orclaim 20 , wherein said material is rubber or a polymeric material. 22.A mat element as claimed in claim 17 , wherein the trailing edge of eachslot is chamered to lift debris onto the upper surface of the matelement.
 23. A mat element as claimed in claim 22 , wherein the trailingedge of each slot faces perpendicular to the direction of travel.
 24. Amat element as claimed in claim 22 , wherein the training edge of saidslot is inclined to the direction of travel of the mat.
 25. A matelement as claimed in claim 22 , wherein the trailing edge of each slotis inclined at 45° to said direction of travel.
 26. A mat element asclaimed in claim 24 , wherein the trailing edge is provided with fingerelements which project toward said leading edge of said slot.
 27. A matelement as claimed in claim 26 , wherein said grid-like material of saidmat provides a debris support formation rearwardly of said slot havingupper and lower surfaces and wherein said finger elements have an uppersurface which slopes downwardly toward said leading edge of said slot toprovide a chamfer of the trailing edge of each slot and wherein a lowersurface of said finger elements extends marginally below said lowersurface of said support formation.
 28. A mat element as claimed in claim27 , further having upstanding barrier means for retaining collecteddebris on said upper surface of the support formation.
 29. A mat elementas claimed in claim 28 , wherein said barrier means is comprised of atleast one transverse row of upstanding projections.
 30. A mat element asclaimed in claim 17 , wherein said trailing edge has finger elementsprojecting toward a leading edge of said slot.
 31. A mat for sweeping asurface, the mat having slots through which debris can pass to collecton the upper surface of the mat, as the mat is passed over a surface tobe swept, the mat being formed as a perforate structure having an arrayof first apertures therethrough, and within at least a substantialproportion the first apertures, mesh structures which, within therespective first aperture, present a respective array of secondapertures of substantially smaller size than the first apertures.
 32. Amat as claimed in claim 31 , wherein the elements defining the secondapertures are disposed at locations at or towards bottom edges ofperipheral walls defining the first apertures.
 33. A mat as claimed inclaim 30 or claim 31 , wherein the second apertures are present in asubstantial portion at least of ones of the first apertures spaced awayfrom trailing edges of at least a substantial proportion of the slots,and not present in at least a substantial proportion of the firstapertures adjacent the trailing edges of the slots.
 34. A mat as claimedin claims 31 to 34 , wherein the second apertures are of area in therange 2.25 to 25 mm².
 35. An element for forming a mat as defined in anyone of claims 1 to 17 and 31 to 34 defining at Least one said slot, andan array of first and second apertures, the element having at sidesthereof means for joining the element to like elements to form the mat.36. A mat for sweeping a surface comprising a substantially flat mat ofgrid-like, semi-flexible material having a leading edge for pulling themat over a surface in a direction of travel substantially transverse tosaid leading edge wherein portions of said grid-like material aremissing to define at least one elongated open slot having a leading edgeand a trailing edge extending therethrough and disposed transverselyrelative to the direction of travel whereby debris can pass through eachslot over the trailing edge thereof to collect on an upper surface ofthe mat; wherein at least part of the grid-like material has aperturestherein, being of area in the range 2.25 to 25 mm².
 37. A mat accordingto claim 36 wherein a portion of the grid-like structure adjacent atailing edge of the or each said slot is free of apertures in saidrange.
 38. A mat for sweeping a surface, the mat having slots throughwhich debris can pass to collect on the upper surface of the mat, as themat is passed over a surface to be swept, the mat being formed as aperforate structure, with smaller apertures being provided within cellsof the mat which are defined by upstanding walls of the mat.
 39. A mataccording to claim 38 wherein said perforate structure has apertures ofarea in the range 2.25 to 25 mm².
 40. An element for forming a mat asclaimed in claim 38 or 39 defining at least one said slot and at least aportion of said perforate structure, the element having a peripheralborder element.
 41. An element as claimed in claim 40 having means at anundersuface thereof for maintaining the element above a ground surfaceover which the element is moved in use.
 42. An element as claimed inclaim 41 having transverse walls defining forward and rearward edges ofsaid slot.
 43. An element as claimed in claim 41 or 42 wherein a portionof the element adjacent a trailing edge of the slot is unapertured orhas apertures outside said range.